Fig. 1

Schematic diagram of modified reflex cough test using our new equipment. The new cough reflex testing device consists of a mouthpiece, tube, filter, spirometer (gray arrow), and ultrasound nebulizer (white arrow). The tube is designed as a double pipe (black arrow) with ten holes between the inner and outer pipes. A corrugated tube (white triangle) from the ultrasound nebulizer is connected to the outer pipe, and the spirometer sensor is attached to the inner pipe (black triangle). The microaerosol emitted from the ultrasound nebulizer fills the outer pipe, and is administered to the oral and airway epithelia through the holes and mouthpiece. The cough then passes through the inner pipe to the spirometer sensor